Together with the increase in the use of small size printers in these days, an oil-less fixing process of a toner image has become the mainstream of the fixing method, in which the electrophotographic toner image is fixed without coating oil. Also, use of a considerable amount of crystalline organic compound in the toner as a release agent has recognized to be effective to lower the fixing temperature of the toner image, however, on the other hand, much use of the release agent also disturbs the development of a low temperature fixing toner because of the heat absorption due to the melting heat of the release agent. Alternatively, a technology to add a liquid lubricant to the toner (for example, refer to Patent Documents 1-3), has been proposed, however, when a low viscosity liquid lubricant is kneaded with a resin, viscosity difference tends to be too large and a problem of a poor dispersion may arise. Further, when the toner pulverizes, the pulverization occurs at the interface of the toner particle, where liquid lubricant exists, accordingly, the liquid lubricant is always existing on the surface of the toner or the liquid lubricant is flowing out of the toner surface, resulting in lowering of the fluidity of the toner particles due to the viscosity of the liquid lubricant. As the result, toner supply system may become unstable, and also image defects may become notable. Further, the toner particles may mutually granulate due to the viscosity of the lubricant to form larger granules. Accordingly, such toner has been stored or transported under a strict temperature control, for example, by use of a coolant, because of the poor storage stability.
Patent Document 1: Japanese Patent Publication Open to Public Inspection (hereafter referred to as JP-A) No. 8-22149
Patent Document 2: JP-A No. 8-272133
Patent Document 3: JP-A No. 9-269685